深圳大学学报理工版

通过对应力及电势垒的周期调制,在石墨烯及类石墨烯蜂窝格子材料中泵浦出能谷流.应力在能谷K和K'处诱导的符号相反的矢势,等效于加载K和K'能谷处的应力泵浦信号间有一个π相位差,导致纯能谷流的产生.当在含有自旋轨道耦合的类石墨烯蜂窝格子材料中存在一个交错子格子势时,经由自旋-能谷锁定相,泵浦出的纯能谷流可伴随着纯的自旋流.再引入一个交换场后,可通过泵浦得到电荷流、能谷极化流以及自旋极化流.

We propose a scheme for the pumping of bulk valley current in graphene and graphene-like honeycomb crystals by cyclic modulation of the strain and an electric potential barrier. The strain-induced opposite vector potentials at K and K' valleys generate a π phase difference between the pumping signals of strain in two valleys, which leads to a pure valley current. In graphene-like honeycomb crystals with spin-orbit coupling, the pumped pure valley current can be accompanied by a pure spin current via the spin-valley locked phase in the presence of a staggered sublattice potential. The charge current, valley-polarized current, and spin-polarized current can also be pumped when an exchange field is applied.

引言
1 模型与方法
2 结果及讨论
3 结语

图1 基于类石墨烯六角格子的纯能谷流泵浦示意图<br/>Fig.1(Color online)Schematic illustration of the proposed pure valley current pump based on graphene-like honeycomb crystals

图1 基于类石墨烯六角格子的纯能谷流泵浦示意图
Fig.1(Color online)Schematic illustration of the proposed pure valley current pump based on graphene-like honeycomb crystals

图2 不同静态参数A0与U0下泵浦的电荷流及能谷流作为费米能的函数<br/>(L1=L2=L3=100 nm,λ=1 meV, Δz=h=0)<br/>Fig.2(Color online)The pumped charge current and valley current versus the Fermi energy for different static parameters A0 and U0.

图2 不同静态参数A0与U0下泵浦的电荷流及能谷流作为费米能的函数
(L1=L2=L3=100 nm,λ=1 meV, Δz=h=0)
Fig.2(Color online)The pumped charge current and valley current versus the Fermi energy for different static parameters A0 and U0.

图3 在L2区域引入交错子格子势后泵浦出的自旋流与能谷流<br/>(L1=L2=L3=100 nm, A0=1 meV, U0=10 meV, h=0)<br/>Fig.3(Color online)The pumped spin currents and valley currents for various parameters

图3 在L2区域引入交错子格子势后泵浦出的自旋流与能谷流
(L1=L2=L3=100 nm, A0=1 meV, U0=10 meV, h=0)
Fig.3(Color online)The pumped spin currents and valley currents for various parameters

图4 不同交换场下Ic, Iv, Is作为费米能的函数及固定费米能EF=25 meV时Ic对h的依赖<br/>(λ=Δz=1 meV, L1=L2=L3=100 nm, A0=1 meV, U0=10 meV)<br/>Fig.4(Color online)Ic, Iv, Is versus EF for different h, and Ic versus h for fixed EF=25 meV

图4 不同交换场下Ic, Iv, Is作为费米能的函数及固定费米能EF=25 meV时Ic对h的依赖
(λ=Δz=1 meV, L1=L2=L3=100 nm, A0=1 meV, U0=10 meV)
Fig.4(Color online)Ic, Iv, Is versus EF for different h, and Ic versus h for fixed EF=25 meV

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备注

引言

1 模型与方法

2 结果及讨论

3 结语

期刊信息

备注

引言

1 模型与方法

2 结果及讨论

3 结 语

期刊信息

3 结语